Secret and Joke Content
Large amounts of content has been hidden in Fiend Folio that act as jokes or "easter eggs". Some of them can be found through rare encounters, or through doing certain actions, while most others can only be found through the use of the game's debug console.
Characters
Fiend Folio: Reheated features 3 secret characters who can not be played as they are hidden by default, and can only be accessed by entering commands in the debug console, or by editing the players.xml
file in the MOD's folder.
A tutorial for how to edit the players.xml
file and make the hidden characters visible can be found here:
Enemies
Golden Fly Enemies
Golden Boom Fly
An enemy that very rarely can replace regular Boom Flies. Upon death, turns the entire room into gold similar to Ultra Greedier, and drops a large number of random coins on the ground.
Golden Mightfly
A very rare version of Mightfly that, similarly to a Golden Boom Fly, turns the room gold upon death. Also shoots out 3 V-shaped coin projectiles, as well as a fountain of coin projectiles on death. Each of these projectiles will spawn a single Penny.
Shine Spit
A golden version of Spit that, upon death, lobs a golden projectile that explodes upon landing. This projectile also leaves behind a trail of golden tears that fall to the ground and explode upon landing. The trail each spawns a Penny when they explode, with the final explosion turning the room golden and spawning a larger amount of Coins.
Notes
- Golden Boom Flies, Golden Mightflies and Shine Spits each have a 0.02% chance to replace their respective enemy type. This chance can be doubled based on if the player:
- Has a debt of 99 with Dad's Wallet
- Is holding Shiny Rock
- Is holding Nitro Crystal
- If the player has all three of these, the chance for one of these enemies to appear will be 0.16%.
- A Golden Boom Fly can appear in a single, very rare I AM ERROR room.
Nuclear Throne Enemies
Secret enemies in Fiend Folio that originate from the game Nuclear Throne.
These enemies, excluding Fish from Nuclear Throne and IDPD Gary, can be found randomly in rooms when Popo Modo is enabled in the Dead Sea Scrolls options menu.
IDPD Grunt
Runs around the room, shooting 2-4 laser bolts at Isaac, occasionally rolling to dodge attacks or if the player comes too close. Rarely throws a grenade at Isaac that magnetises him and other enemies towards it, before exploding after a few seconds.
IDPD Inspector
Runs around the room, firing a single, large laser bolt at Isaac. Will also occasionally create a magnetic effect, pulling Isaac towards itself.
IDPD Shielder
Runs around the room, shooting a large array of laser bolts at Isaac.
Occasionally upon taking damage, it will turn itself into a large metal block, where it will remain stationary and be unable to attack. Shooting at this block will deflect all of Isaac's tears back towards him.
After a short moment, the Shielder will turn back to normal.
Fish from Nuclear Throne
An enemy that looks like Fish from Nuclear Throne. It can extremely rarely spawn from Portals or the portals from Wormhole Rock.
Similar to the character it refers to, it runs around the room, firing bullets at Isaac. Occasionally it will roll to dodge incoming tears, making it quite a tricky opponent.
- If Fish from Nuclear Throne is in the same room as the IDPD enemies, they will stop targeting Isaac and begin fighting each other, until one or the others are dead.
- Fish from Nuclear Throne and the IDPD will leave behind corpses on death. These have no collision and can't be interacted with.
IDPD Gary
IDPD Gary, also known as Interdimensional Police Department Gary or just Portal Gary, is a variant of Gary that spawns swarms of IDPD Grunts instead of random Maggots. Can extremely rarely spawn from Portals.
Super Easy Mode
Two enemies exclusively found in Super Easy Mode:
Easy Woodburner
All enemies in Super Easy Mode will be replaced with a Woodburner variant that has no plank through its head and has a very bright color palette. It will only follow Isaac without attacking, and deals no damage whatsoever. When touched, it becomes friendly, and when killed, it will release multiple fireworks. Easy Woodburners that have been made friendly will seek out other Easy Woodburners to make them friendly as well.
Easy Ghostse
All bosses in Super Easy Mode will be replaced with an easy variant of Ghostse. It looks exactly the same as its normal counterpart but deals no damage, and its main attack is replaced with spawning a single Rainbow Poop. When touched, it becomes friendly, and when killed, it will release multiple fireworks.
Shiny Fishface
Shiny Fishface are rare variants of Fishface, having a 1/4,096 chance of replacing one. Shiny Fishface behave exactly the same as their regular counterparts, with the only differences are that it has a different palette and creates sparkling particles. It also spawns a single Drowned Charger upon death.
- Shiny Fishface is a reference to Pokémon, specifically the Pokémon Gyrados in its Shiny form, as Shiny Fishface features a similar coloration. The chance for Shiny Fishface to appear is also a similar chance for an encountered Pokémon to be a Shiny in some generations of Pokémon.
- The chances of finding a Shiny Fishface are doubled if the player is holding Shiny Rock.
Sneaky Retriever
Sneaky Retrievers have a 0.1% chance to replace Dogrocks. Unlike normal Dogrocks, they do not have any attacks and will simply sit there while spinning their eye around.
Baba
A character from a puzzle game Baba IS You. It moves around in cardinal directions, creating dust clouds behind it. Does not deal contact damage.
- Baba used to appear whenever the mod's grids (rocks, key blocks, etc) were broken, but no longer does this as of The Reheated Update.
Mern
A ridiculously powerful enemy that appears only in Mern Mode, where it replaces every other enemy.
Mern moves very erratically at incredible speed, making killing it incredibly difficult, if not nearly impossible. Mern constantly scatters spectral homing tears around and spams random sound effects with random pitch.
Upon death, Mern spawns an enormous swarm of Dart Flies that easily fill up an entire room. Mern can also become a champion, making it even harder to kill.
Black Maw With Eyes
Rarely, when a Black Maw spawns, it will appear to gain goofy-looking eyes. Black Maws With Eyes have no changes in their behavior.
Drowned Attack Fly
An Attack Fly that flashes blue instead of red. Behaves like a regular fly but explodes into four diagonal blood shots and spawns a Drowned Charger on death.
Spider (Nicalis)
A grey Gaper with its face replaced with a cropped, low-res image of Spider, the creator of "SpiderMod", a mod for The Binding of Isaac: Wrath of the Lamb. Upon death, the screen shakes, and a pop-up text saying "Overwatch" appears, while a well-known music bit from the FPS game Overwatch plays.
- Spider (Nicalis) appears prominently as an enemy in a hidden StageAPI custom stage, The Stony Level.
Hungry Para-Bite
A variant of a Para-Bite that looks and acts identically to a regular Para-Bite, except when Isaac takes damage from it, it transforms into a Roundy.
- This is a joke about how in the Ipecac mod, One Tooths used to turn into Fat Bats when Isaac gets hit by them.
Bighead
A Gaper with a giant head which acts like a regular Gaper, but spawns a lot more gibs when it dies and also has extra armor.
Horses & Ponies
Fiend Folio: Reheated adds different variants of Horses and Ponies to the MOD that wander around, some having different behavior or attacks.
These Horses can be found randomly in rooms when Stable Mode is enabled in the Dead Sea Scrolls options menu.
Trihorf
A variant of Horf that, as you might expect, shoots 3 tears at a time instead of one.
- Trihorf possibly originates from the Eternal Monsters mod; however, this enemy is more likely a riff on the idea of a "triple shot Horf" being seen as low-hanging fruit.
- Trihorf can appear very rarely in a single room in the Basement. In this room, it has roughly a 1% chance for one of the two Horfs to be replaced with Trihorf.
Golden Spider
Behaves like a regular Spider. Upon death, has a chance to revive itself and appear in a random spot in the room, similar to the effect of Golden Pennies.
Thumbs-up Fly
Behaves like a regular Fly. Touching it will cause Isaac to make a positive "thumbs up" gesture, while killing it will cause him to do the negative "head down" gesture.
- 2 Thumbs-up Flies can appear in a very rare Super Secret Room layout with an item pedestal.
Grinner
Behaves somewhat like a Gaper but with greatly increased speed. Will attempt to stay within a certain distance close to Isaac while avoiding touching him, and occasionally pauses to make an obnoxious giggling sound.
- Grinner is a reference to a video, consisting of a still image of a Trendylocos Gogo figurine accompanied with the same giggling sound that Grinner makes,[1] which has become an inside joke between members of the Fiend Folio Cornmunity Discord server.
Fly Who Has Green And Long Body
A variant of an Army Fly that is very long and thin. It behaves exactly the same as an Army Fly, except for having more health.
Shady Host
A variant of Host which shoots out 3 black and red flashing tears. Upon hitting a wall, each of these tears will split into 3 more tears towards Isaac. When it closes its shell after this attack, it creates cascades of bloody explosions toward Isaac.
- There is a single room in the Dark Room which houses a Shady Host. This room is called Black for Black for Black and also contains a Shady, a Slim Shady, and 6 Black Sacks on top of Lily Pads.
Crudemate
Crudemate is a very rare enemy that spawns in the Dank Depths. Their only behavior is to run to a nearby Grate, where they will jump in and disappear. They are only guaranteed to spawn in a single room which has a weight of 0.1 and only one entrance, making them a very rare enemy to encounter. They can also appear in 2 other rooms, however, these rooms have a weight of 1.0, and Crudemate only has a 2% chance to spawn in them.
- Crudemate is a reference to the game Among Us.
- A tiny Crudemate can be seen inside Junkstrap when it dies.
- There is an incredibly rare room in The Void named "Emergency Meeting", which holds 7 Crudemates and a Kill Plate. This is a reference to Emergency Meetings from Among Us, the game which the Crudemate originates from.
Cave Spider
Another rare enemy, the Cave Spider only spawns on the Mines floor, and only appears in a single room which has one entrance. The Cave Spider behaves similarly to a Level 2 Spider, however, it is unable to kill Isaac, it can only reduce their health to half a heart. While at half a heart, the Cave Spider will not deal any contact damage.
- Cave Spider is a reference to the game Minecraft. Its inability to deal lethal damage to the player is a nod to how poison works in Minecraft, always leaving the player at half of a heart.
- Caves Spider was from the cancelled Morbus mod, where it appeared in a single room in the Caves.
- If playing as Keeper, it can only reduce them to 1 Coin Heart.
- If playing as The Lost, it can deal no damage.
Psychic Mr. Maw
Psychic Mr. Maw is a fusion between a Mr. Maw and a Psychic Maw. It spawns with an Eternal Fly circling the head, and when close enough to Isaac, launches its head and shoots a homing projectile. If the body is destroyed first, the head becomes a normal Psychic Maw. If the head is destroyed first, the body turns into a unique Gusher that bleeds homing projectiles.
- This enemy only appears in a single vertical 1×2 room in the Depths, all alone.
- This enemy was added due to a fan suggestion on the Fiend Folio Cornmunity Discord server.
Maw Mr.
An enemy that looks identical to a Mr. Maw, and behaves similarly as well, except that it launches its body at the player instead of the head.
- This enemy only appears in a single room in the Depths, along with two normal Mr. Maws.
Sloth's Head
Sloth's Head is a green-colored Black Globin's Head that behaves identically and slides after Isaac, but leaves a trail of green creep instead of red creep. It is meant to be Sloth's Keeper counterpart, like with Desirer and Seducer, but behaves nothing like the other variants.
It appears in 3 rare rooms in the Catacombs, and 1 in Sheol.
Notes
- Sloth's Head not only has a lazy sprite, but also lazy AI, naming, and implementation, making it the laziest enemy in the game
Tainted Spit
Behaves similarly to a Tainted Sucker — however, it has less health and all of its projectiles explode upon landing, making damage almost unavoidable.
Bosses
Peat
A low-res Peter Griffin from the animated series "Family Guy". Possesses a health bar, similarly to bosses. Usually chases Isaac, occasionally punching him in the face, which will deal damage and send him away with a huge knockback. Occasionally, Peat will teleport, targeting the player's current position and creating an explosion upon doing so.
Notes
- The explosions hurt Peat himself, making it possible for him to accidentally commit suicide.
- Peat appears as a boss in a hidden StageAPI custom stage, "The Stony Level".
- When appearing as a boss in this stage, Peter Griffin has a unique boss portrait with an Isaac-like artstyle, where he appears naked and crying similar to Isaac himself.
- Peat can also appear in a very rare Gehenna room, spawned by a hidden button.
As of the Reheated update, Peat is included within the mod's players.xml file, although is marked as hidden meaning he cannot be played under normal circumstances. Peat starts with 4 Red Hearts and cannot pick up items or pickups of any kind aside from Hearts (whether or not this is intentional or a bug is unknown). He uses the previously mentioned Boss Portrait for his VS and Stage Transition sprites.
The likely purpose of his existence is for this meme posted by Fiend which shows official footage of the player as Peat softlocking themselves in Caves II.
Blue Horf (Boristumous)
What appears to be some sort of a Husk variant on the portrait, is actually a recolored Horf. Its attacks consist of:
- Moving erratically.
- Creating a fart cloud that heavily knocks Isaac away and spawning a Corny Poop.
- Coughing up a swarm of Flies and Attack Flies.
- Releasing a small ring of flames.
- Firing a large blood shot that leaves a trail of damaging creep.
After death, it replaces floor underneath itself with a pit.
Notes
- This boss is a reference to one of the episodes of the modding tutorial made by BroskiPlays, "CUSTOM ENEMIES FROM SPRITES TO LUA".
- Boristumous appears as a boss in a hidden StageAPI custom stage, "The Stony Level".
Duke of Demons
Appears to be a demonic variant of Duke of Flies. It possesses two attacks:
- Fires a gigantic Brimstone beam towards the player.
- Spawns three "Demon Babies" that slowly float towards Isaac and fire blood shots at him when nearby.
Notes
- The Duke of Demons used to be in an older version of the Genesis mod, back when it was called The Binding of Jesus: Holybirth. He was a plain reskin and didn't have any wings, however.
Jackson
A pixelated Michael Jackson. He chases Isaac while moonwalking, occasionally performing a kick that creates an explosion. Eventually, he starts to spin around while creating spark particles. While spinning, he will loosely chase Isaac, similar to Lust.
- The explosions hurt Jackson himself, making it possible for him to accidentally commit suicide.
Mouse
A png of a mouse, which possesses a boss bar. When spawned in, it will turn red and quickly charge towards the player, instantly killing them on contact. Managing to kill it will not drop any rewards. If mouse control is enabled, Mouse will instead follow the cursor but grow increasingly agitated if not moving. After a while of inactivity, it will begin spawning troll bombs before enraging and chasing Isaac as normal.
Miku
Miku is joke 'boss' which can be encountered in a single Crawl Space that can not be entered without using console commands. The Crawl Space consists of 2 sets of 4 platforms with 2 ladders on each side. Miku will be standing at the very right of the screen, and after a second, she will begin to attack the player. She attacks by shooting fruits at the player, which come in multiple waves of difficult patterns. Touching a fruit will instantly kill the player. Miku herself cannot be attacked, and after approximately 1 minute and 45 seconds, she will simply disappear. If the player does not have a flight, they will be unable to leave the Crawl Space.
- The boss fight is a reference to the game I Wanna Kill the Kamilia 3, where she also appears as a boss with a similar layout and attacks.
Minamitsu Murasa
Minamitsu Murasa as she appeared in the game Touhou Seirensen ~ Undefined Fantastic Object. She features identical attack patterns from the aforementioned game.
Hidden Custom Stages
Accessible through debug console commands are three custom floors made through StageAPI.
Stony Level
A floor with the Primordial Caves backdrop. As the name suggests, the rooms of this floor contain a slew of Stoneys, as well as the joke enemy Spider (Nicalis).
In the Boss room, The boss of the floor will be replaced by either Peat or Boristumous.
The console command to load the the Stony Level is: cstage Stony Level
- Note: Command is case-sensitive
Lab
A floor featuring a deep dark laboratory backdrop, with its own unique rock and pit textures.
Despite appearances, the floor does not feature any custom rooms, instead copying its rooms and bosses from Necropolis.
- Note: There is a luaroom file titled "theLab.xml" that contains custom rooms, yet goes unused for this floor.
The console command to load the Lab is: cstage Lab
- Note: Command is case-sensitive
Morbus (Real)
A floor that may appear at first glance to be Morbus, but in actuality is merely a floor with a Utero backdrop that has been colored black.
Morbus (Real) also does not feature any custom rooms or even those from Chapter 4, instead copying its rooms and bosses from Catacombs.
The console command to load Morbus (Real) is: cstage MorbusReal
- Note: Command is case-sensitive
Beggars and Machines
Phone Booth
The Phone Booth is a very rare machine that only appears in a 0.1 weight I AM ERROR Room, and in a single Shop layout with only a 0.1% chance to spawn. The Phone Booth will randomly start to ring, and interacting with it will cause the game's music to lower and special audio to be played. The player will be attached by a cable to the machine, and can only move in a small area around it. Interacting with the machine again will hang up the phone.
- The audio that plays is from the mobile game Talking Ben.
- Bombing the machine will not drop anything.
Cosplay Beggar
The Cosplay Beggar is a very rare Beggar variant which can only appear in a single very rare Secret Room layout with a weight of 0.01, or from using XX - Judgement that has a 0.001% chance of occurring. They take 5 cents at a time and have a chance to pay out with 3 random pickups. These pickups can be any type of Coin, Bomb or Key or Heart. They also have a chance to pay out with the Perfectly Generic Object item, where they will then disappear.
- The Beggar can drop troll bombs, causing it to kill itself if the bombs are not moved away.
- Bombing the Beggar does not affect Devil Deal chances and has a low chance to drop one random pickup.
- The Beggar is a reference the Trolls from to the webcomic Homestuck.
Grid Entities
Dog Doo
The Dog Doo is a poop with a static overlay. When destroyed, it triggers the Glowing Hourglass effect once; going back and destroying it will not trigger the effect again.
Dog Doo can only appear in one room in the Basement during the Ascent.
Special Marked Rocks
If Marked Skulls are placed in a room with a backdrop different than that of a Chapter 3, they will have a unique appearance, with many of them being easter eggs, references, or self-inserts of the developers of Fiend Folio.
Some of these rocks can be found in a few very rare room layouts, including Super Secret Rooms.
Cellar's marked skull; Gummy's character Abi.
The marked skull for the Smoky Basement backdrop; one of Sunil_B's characters.
Downpour's marked skull; a bucket holding an Axolotl; possibly in reference to Minecraft.
Dross's marked skull; a bucket holding Vermin's avatar.
The marked skull for Dross's Peepee backdrop; a bucket with a Peepisser peeking out of it.
Catacomb's marked skull; Ciirulean (Cadence)'s Taffy Wasp character.
Flooded Cave's marked skull; Peas's character Camelia.
Mine's marked skull; Snake Blocks from the Mario series, also referring to developer SnakeBlock.
Ashpit's marked skull; a Flesh Maiden's broken shell.
Mausoleum's marked skull; Pkpseudo's character Tenebria.
Gehenna's marked skull; Tricky from the Madness Combat web-series.
Womb's marked skull; Budj's squid character.
Utero's marked skull; Cake's avatar.
Scarred Womb's marked skull; JonTheRealJon's character Henry.
Blue Womb's marked skull; Creep's character Jumpscare.
Corpse's marked skull; Peas's avatar.
The marked skull for Corpse's blue backdrop; a fat creature vomiting out its own guts, inspired by the "mud monster" from the film The Brothers Grimm.[2]
The marked skull for Corpse's bloody rooms; Minichibi's character.
Corpse's Morbus backdrop; a dead tooth.
Cathedral's marked skull; One of SadlyJustAl's characters.
Sheol's marked skull; Erfly's avatar.
Chest's marked skull; a plushie of Fiend.
Dark Room's marked skull; a purple pentagram with a 0 - The Fool card in the middle.
Shop's marked skull; a piggy bank that looks like Retribution's Mammon.
Arcade's marked skull; Sbody's avatar.
Secret Room's marked skull; NotYourSagittarius's character Mycena.
The marked skull for the Luscious Crawlspace; a tree sprout with a big dumpy.
The marked skull for the Ossuary Crawlspace; A face in a rock, possibly inspired by Han Solo from Star Wars frozen in carbonite.
The marked skull for the Fortress Crawlspace; a golden pyramid with an eye in the middle.
Marked skull in Insulation Crawlspace; a 0 - The Fool card betwixt the boards.
The marked skull for Error Rooms; a compressed image of a trollface.
A marked skull for when you use the D12 or Eternal D12; a cube-shaped skull with an X on it.
Other Secrets and Jokes
Trans Brimstone
Whenever the player fires a Brimstone laser, there is a 0.001% chance the beam will have the colors of the Transgender Flag. This doesn't apply to Technology lasers, the Mega Blast laser, or enemy Brimstone lasers.
Vein Slide Whistle Easter Egg
There is a 1/5000 chance that a Vein moves out of the way upon a pickup landing on top of it.
Slide whistle sound included!
Secret Death Jingle
When the player gets a Game Over, there is a 0.5% chance for different music will play instead of the normal game over music.
- This easter egg is a reference to The Devil's Harvest, where this track was the mod's default game over theme.
Secret Mode
Typing "secret" with the console closed in the starting room will enable Secret mode
"Fiend has found your password" will appear in the console upon activation, along with a laugh sound
A lot of random chaos will occur, such as:
- Dark Easu spawning
- Entities spinning rapidly
- The room filling with random pickups, and then eventually all of them exploding after a few seconds
- All entities getting random velocity, teleporting on Isaac, changing into random enemies or changing colour
...And more!
4:20 Weed Secret
Isaac smokes a fat joint when the following criteria are met:
- The game timer is 4:20.
- The run has not been exited.
- The player is currently playing as Isaac.
- The player has picked up no items. (With the exception of Isaac's current starting items.)
Sanguine Hook Secret
When playing the Isaac Rebuilt challenge, if you mash the sanguine hook up against the wall enough times, a note will appear asking you to stop, if you continue, it'll ask again to stop, but if you keep going for long enough you can find multiple responses from the note appear. Upon mashing Sanguine Hook against a wall for a total of 1 million times, the player will be granted a gold skin for Sanguine Hook as a reward for their commitment. This golden hook is only cosmetic, and will only appear during the Isaac Rebuilt challenge.
Master Atom
Found in a single I AM ERROR Room, spawned by a button. Plays its own dubstep theme music when it appears. Otherwise remains stationary and cannot be interacted with in any way.
- Master Atom is a reference to the @3Dgifdubstep Twitter account, specifically this post.
Fiend Folio Shopkeeepers
A set of dead Shopkeepers, some of them resembling Fiend Folio devs.
They do not seem to appear anywhere, and merely exist in the game's files.
Reheated Content
The Binding of Isaac: Reheated
This enemy is a reference to The Binding of Isaac: Reheated, a mod concept made by one of Fiend Folio developers, Minichibis, a long time ago. It appears as a sprite-sheet of some of the "reheated" enemies and possesses a bunch of attacks:
- Constantly fires blood shots in random directions.
- Fires a Brimstone beam in the player's direction.
- Teleports, spawning a random Reheated enemy in its previous location.
Reheated Chest
A chest variant that requires a key to open. When opened, spawns a random Reheated enemy.
Beserker
A red creature that somewhat resembles Mern. While Isaac is far away, it slowly floats towards him. If he gets closer, Beserker opens its eyes and begins to fire a constant stream of blood shots. This enemy is likely a reference to the Behelit from the manga series Berserk.
Reheated Gurgle and Cyclopia
The Reheated Cyclopia runs at Isaac trailing red creep behind it, and spitting a barrage of tears at him that leave creep when they land. The Reheated Gurgle does the exact same thing, but the barrage of tears explode when they land instead.
Reheated Charger, Fly and Spider
These three behave like their regular counterparts, with an addition of constant trail of red damaging creep. Unlike the other two, the Reheated Charger will also launch a large cluster of blood tears into the air upon death.
Reheated Hosts
The Webbed Reheated Host will spit a large cluster of baby spiders, the Reheated Host with a big mouth will fire a Brimstone beam to the left or right and the Toxic Reheated Host will spit an arcing projectile that, upon landing, will leave creep and release 3 shots in a spread to the player's current location.
Bobby Fly and Spider
These two leave a fused bomb upon death.
Chompy Fly and Spider
These two occasionally create fountains of blood shots. They heavily resemble Fissures, an enemy from Antibirth.
Sacky Fly and Spider
These two spawn two Spiders upon death.
Icky Fly and Spider
These two fire a single Ipecac shot upon death.
Icky and Techy Creep
Icky Creep fires Ipecac shots and Techy Creep fires Technology lasers when lined up with the player.
THE MOTHER ORB
References